Conductors and Insulators: Classification of Materials

Classification of Materials

• Conductors: materials that allow charge to move freely through them, examples include metals like copper, aluminum, and silver.
• Free electrons in conductors are not bound to atoms and can move relatively freely through the material.
• Insulators: materials in which all electrons are bound to atoms, examples include glass, rubber, and wood.
• Electrons in insulators cannot move relatively freely through the material.
• Semiconductors: materials with electrical properties between those of conductors and insulators, examples include silicon and germanium.

Induced Charge

• An induced charge occurs when a nearby charged object causes a separation of positive and negative charges within a neutral object.
• Steps for charging an object by induction:
  • Bring a negative rod near a neutral object.
  • Electrons in the object are repelled to the opposite end, causing one end to become positive.
  • If the object is grounded, electrons from the negative end travel into the ground.
  • The object becomes positive due to an excess of protons.

Charging an Object

• There are three main methods of charging an object:
  • Charging by Friction (Rubbing): electrons are transferred from one material to another, resulting in one material becoming negatively charged and the other positively charged.
  • Charging by Contact: electrons are transferred from a negatively charged object to a neutral or positively charged object through direct contact.
  • Charging by Induction: the movement of electrons within a substance caused by a nearby charged object, without direct contact between the substance and the object.